The purpose of this study is to investigate different statistical methods of analyzing microbiological changes in plaque. There are three different approaches to the study of this situation. The simplest approach is through the use of univariate analysis of variance. The second approach is based on the multivariate analysis of vaiance technique. A third approach is based on the polynomial growth curve model, i.e. a separate polynomial growth curve is fit for each group. All three different methods will be performed on the recent NCP experiment -- "Natural transmission of streptococcus mutans among rats consuming diets containing different concentrations of sucrose." This study is being undertaken to at tempt to evaluate the advantages and disadvantages of different statistical methods of analyzing microbiological changes in plaque.